1. Technical Field
The present invention relates to an actuator control device, an optical module, an electronic apparatus, and an actuator control method.
2. Related Art
In the related art, a variable wavelength interference filter including a pair of substrates facing each other, reflective films respectively disposed in each substrate and facing each other, and electrodes respectively disposed in each substrate and facing each other is known (for example, JP-A-1-94312).
In the variable wavelength interference filter described in JP-A-1-94312, electrostatic capacitance monitor electrodes facing each other and electrostatic force applying electrodes (electrostatic actuator) facing each other are respectively disposed in each substrate. In such a variable wavelength interference filter, a voltage is applied to the electrostatic actuator by a control circuit and thereby a gap amount (interval dimensions) between reflective films is changed. In addition, a potential of the electrostatic capacitance monitor electrode is detected by an electrostatic capacitance detection circuit and the voltage applied from the control circuit to the electrostatic actuator is finely adjusted (feedback control) based on detected electrostatic capacitance, and thereby the gap amount of the gap between the reflective films can be set to a desired target value.
However, in the electrostatic actuator described in JP-A-1-94312, a drive amount when applying a predetermined drive voltage may be changed (drive characteristics are changed) by environmental factors such as a temperature change or a temporal change, and the like. For example, if an initial gap of the electrostatic actuator is changed, since the drive amount when applying the voltage is changed, the drive characteristics are also changed. As described above, if the drive characteristics are changed, it is necessary to perform gain control for resetting an appropriate gain also in the drive circuit of the electrostatic actuator.
However, in the feedback control using a fixed gain of the related art described in JP-A-1-94312, there is a problem that appropriate gain control cannot be performed and an optimal feedback control is unlikely to be performed, and for example, a time for setting the electrostatic actuator to the target value is long or abnormal oscillation occurs.